Note: The following is a mailing list posting by John Dunlavy, a well known
audio designer. I stashed a copy of this posting because I wanted to cite it in
my stereo equipment page, and at the time there were
no good repository of the mailing list or usenet articles that was accessible via a
stable URL. I would suggest you check out
audio postings by dunlavy
for even more information.

Having read some of the recent comments on several of the Internet
audio groups, concerning audible differences between interconnect and
loudspeaker cables, I could not resist adding some thoughts about the
subject as a concerned engineer possessing credible credentials.

To begin, several companies design and manufacture loudspeaker and
interconnect cables which they proudly claim possess optimized electrical
properties for the audiophile applications intended. However, accurate
measurements of several popularly selling cables reveal significant
differences that call into question the technical goals of their designer.
These differences also question the capability of the companies to perform
accurate measurements of important cable performance properties. For
example, any company not possessing a precision C-L-R bridge, a Vector
Impedance Meter, a Network Analyzer, a precision waveform and impulse
generator, wideband precision oscilloscopes, etc., probably needs to
purchase them if they are truly serious about designing audio cables that
provide premium performance.

Measurable properties of interconnect cables include all of the above,
with the addition of those properties of the dielectric material that
contribute to microphonic noise in the presence of ambient
vibration, noise, etc. (in combination with a D.C. off-set
created by a pre-amp output circuit, etc.).

While competent cable manufacturers should be aware of these
measurements and the need to make them during the design of their
cables, the raw truth is that most do not! Proof of this can be found
in the absurd buzzard-salve, snake-oil and meaningless advertising
claims found in almost all magazine ads and product literature for
audiophile cables. Perhaps worse, very few of the expensive, high-tech
appearing cables we have measured appear to have been designed in
accordance with the well-known laws and principles taught by proper
physics and engineering disciplines. (Where are the costly Government
Consumer Protection people who are supposed to protect innocent
members of the public by identifying and policing questionable
performance claims, misleading specifications, etc.?) --- Caveat
Emptor!

For example, claiming that copper wire is directional, that
slow-moving electrons create distortion as they haphazardly carry
the signal along a wire, that cables store and release energy as
signals propagate along them, that a final energy component
(improperly labeled as Joules) is the measure of the tonality
of cables, ad nauseum, are but a few of the non-entities used in
advertisements to describe cable performance.

Another pet peeve of mine is the concept of a special
configuration included with a loudspeaker cable which is
advertised as being able to terminate the cable in a matter
intended to deliver more accurate tonality, better imaging, lower
noise, etc. The real truth is that this special
configuration contains nothing more than a simple, inexpensive
network intended to prevent poorly-designed amplifiers, with a
too-high slew-rate (obtained at the expense of instability caused by
too much inverse-feedback) from oscillating when connected to a
loudspeaker through a low-loss, low-impedance cable. When this
box appears at the loudspeaker-end of a cable, it seldom
contains nothing more than a Zobel network, which is usually a
series resistor-capacitor network, connector in parallel with
the wires of the cable. If it is at the amplifier-end of the cable, it
is probably either a parallel resistor-inductor network,
connected in series with the cable conductors (or a simple cylindrical
ferrite sleeve covering both conductors). But the proper place for
such a network, if it is needed to insure amplifier stability and
prevent high-frequency oscillations, is within the amplifier - not
along the loudspeaker cable. Hmmm!

Having said all this, are there really any significant audible
differences between most cables that can be consistently identified by
experienced listeners? The answer is simple: very seldom! Those who
claim otherwise do not fully grasp the power of the old Placebo-Effect -
which is very alive and well among even the most well-intentioned
listeners. The placebo-effect renders audible signatures easy to detect
and describe - if the listener knows which cable is being heard. But, take
away this knowledge during blind or double-blind listening comparisons and
the differences either disappear completely or hover close to the level of
random guessing. Speaking as a competent professional engineer, designer
and manufacturer, nothing would please me and my company's staff more than
being able to design a cable which consistently yielded a positive score
during blind listening comparisons against other cables. But it only rarely
happens - if we wish to be honest!

Oh yes, we have heard of golden-eared audiophiles who claim to be able
to consistently identify huge, audible differences between
cables. But when these experts have visited our facility and were put
to the test under carefully-controlled conditions, they invariably
failed to yield a score any better than chance. For example,
when led to believe that three popular cables were being compared,
varying in size from a high-quality 12 AWG ZIP-CORD to a high-tech
looking cable with a diameter exceeding an inch, the largest and
sexiest looking cable always scored best - even though the CABLES WERE
NEVER CHANGED and they listened to the ZIP Cord the entire time.

Sorry, but I do not buy the claims of those who say they can always audibly
identify differences between cables, even when the comparisons are properly
controlled to ensure that the identity of the cable being heard is not
known by the listener. We have accomplished too many true blind
comparisons with listeners possessing the right credentials, including
impeccable hearing attributes, to know that real, audible differences
seldom exist - if the comparisons are properly implemented to eliminate
other causes such as system interactions with cables, etc.

Indeed, during these comparisons (without changing cables),
some listeners were able to describe in great detail the big
differences they thought they heard in bass, high-end detail,
etc. (Of course, the participants were never told the NAUGHTY
TRUTH, lest they become an enemy for life!)

So why does a reputable company like DAL engage in the design and
manufacture of audiophile cables? The answer is simple: since
significant measurable differences do exist and because well-known and
understood transmission line theory defines optimum relationships
between such parameters as cable impedance and the impedance of the
load (loudspeaker), the capacitance of an interconnect and the input
impedance of the following stage, why not design cables that at least
satisfy what theory has to teach? And, since transmission line theory
is universally applied, quite successfully, in the design of cables
intended for TV, microwave, telephone, and other critical applications
requiring peak performance, etc., why not use it in designing cables
intended for critical audiophile applications? Hmmm! To say, as some
do, that there are factors involved that competent engineers and
scientists have yet to identify is utter nonsense and a cover-up for
what should be called pure snake oil and buzzard salve - in
short, pure fraud. If any cable manufacturer, writer,
technician, etc. can identify such an audible design parameter that
cannot be measured using available lab equipment or be described by
known theory, I can guarantee a nomination for a Nobel Prize.

Anyway, I just had to share some of my favorite Hmmm's, regarding cable
myths and seemingly fraudulent claims, with audiophiles on the net who may
lack the technical expertise to separate fact from fiction with regard to
cable performance. I also welcome comments from those who may have other
opinions or who may know of something I might have missed or misunderstood
regarding cable design, theory or secret criteria used by competitors to
achieve performance that cannot be measured or identified by conventional
means. Lets all try to get to the bottom of this mess by open, informed and
objective inquiry.

I sincerely believe the time has come for concerned audiophiles, true
engineers, competent physicists, academics, mag editors, etc. to take a
firm stand regarding much of this disturbing new trend in the blatantly
false claims frequently found in cable advertising. If we fail to do so,
reputable designers, engineers, manufacturers, magazine editors and product
reviewers may find their reputation tarnished beyond repair among those of
the audiophile community we are supposed to serve.